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PN scrambler for peak-to-average power ratio reduction in OFDM systems for range extension and lower power consumption.

机译：PN加扰器，用于降低OFDM系统中的峰均功率比，以扩展范围并降低功耗。

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摘要

Orthogonal Frequency Division Multiplexing (OFDM) is used in many wireless communication systems due to its robustness towards fading channel behavior and a relative ease of implementation coming from computationally efficient Inverse Fast Fourier Transforms (IFFT). Multicarrier waveforms for digital communications require the summation of multiple frequency-spaced single-carrier signals prior to transmission through a power amplifier (PA). OFDM is a spectral-efficient, multicarrier technique that utilizes hardware efficient IFFT in order to modulate each individual subcarrier with a QAM symbol and sum the carriers together to produce a single time-domain waveform. The addition of multiple sinusoids modulated with random amplitude and phase produces a Gaussian distributed time-domain signal with a large peak-to-average power ratio (PAPR). As a result, the average power into the PA must be backed-off to avoid clipping of the time-domain signal peaks. Clipping of the signal significantly increases in-band noise (IBN) and out-of-band noise (OBN) which adversely increases the bit-error rate (BER) and adjacent channel interference (ACI), respectively. The large backoff required to avoid clipping and provide operation in the linear region of the PA requires use of higher power amplifiers at the transmitter which greatly increases the system's DC power consumption. The methods described in this document allow for PAPR reduction of an OFDM signal by more than 3 dB using a novel pseudo-noise (PN) scrambler technique.;The goal of the research is to improve system power efficiency, while reducing distortion effects. First, an overview of OFDM waveform theory and the PAPR reduction method is provided. Second, extensive probabilistic methods of signals are used to derive new comprehensive analytical equations to predict performance, and allow a system designer to determine the parameters for the PN scrambler technique. Third, an innovative efficient IFFT is presented to allow implementation of the technique with reduced implementation complexity and latency. Fourth, a unique low PAPR preamble is described to provide a complete OFDM packet with PAPR reduction. Finally, a novel power amplifier linearization technique is presented to allow further system power efficiency increase. The simulations and measurements demonstrate significant benefits of the proposed techniques for long-range wireless communications applications.
机译：正交频分复用（OFDM）由于其对衰落信道行为的鲁棒性和来自计算效率高的快速傅立叶逆变换（IFFT）的相对易实现性而在许多无线通信系统中使用。用于数字通信的多载波波形在通过功率放大器（PA）传输之前，需要对多个频率间隔的单载波信号求和。 OFDM是一种频谱有效的多载波技术，它利用硬件有效的IFFT来用QAM符号调制每个单独的子载波并将这些载波相加在一起以产生单个时域波形。多个以随机幅度和相位调制的正弦波相加会产生具有高峰均功率比（PAPR）的高斯分布时域信号。结果，必须降低进入PA的平均功率，以避免削波时域信号峰值。信号的削波显着增加了带内噪声（IBN）和带外噪声（OBN），分别不利地增加了误码率（BER）和相邻信道干扰（ACI）。为避免削波并在PA的线性区域内工作需要较大的补偿，这需要在发射器上使用功率更高的放大器，这大大增加了系统的DC功耗。本文档中描述的方法允许使用新颖的伪噪声（PN）加扰器技术将OFDM信号的PAPR降低3 dB以上。研究的目的是提高系统功率效率，同时减少失真影响。首先，概述了OFDM波形理论和PAPR降低方法。其次，使用广泛的信号概率方法来推导新的综合分析方程式来预测性能，并使系统设计人员可以确定PN加扰器技术的参数。第三，提出了一种创新的高效IFFT，以允许以降低的实现复杂性和延迟实现该技术。第四，描述了唯一的低PAPR前导码，以提供具有PAPR降低功能的完整OFDM数据包。最后，提出了一种新颖的功率放大器线性化技术，可以进一步提高系统功率效率。仿真和测量证明了所提出的技术在远程无线通信应用中的显着优势。

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  • 作者

    Moffatt, Christopher Douglas.;

  • 作者单位

    Florida Institute of Technology.;

  • 授予单位 Florida Institute of Technology.;
  • 学科 Engineering Electronics and Electrical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 414 p.
  • 总页数 414
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 农学（农艺学）;
  • 关键词

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